Sound locator apparatus



May 7, 1940. F. R. HOUSE SOUND LOCATOR APPARATUS Filed Oct. 13, .1937

3 Sheets-Sheet 1 f INVENTOR 64 /YRnNKHLHousE E y May 7, 1940. F, R HOUSE2,199,404

SOUND LOCATOR APPARATUS Filed oc't. 15, 1957 s sheets-sheet 2 INVENTORFYQA Nif Hoz/ss H/s TTOREY May 7, 1940. F, R HOUSE -2,199,404

SOUND LO CATOR APPARATUS Filed oct. 13, 1937 5 sheets-sheet 3 6E .54.INVENTOR fmlvk H. House t'atented May 7, ldd@ -UNETED (STATES enterar.cri-cg 2,199,404 S'LUNL'D LCATR MFARATUS Application @ctober 13, i937,Serial No. lfgld 9 Claims.

A' This invention relates, generally, to apparatus for locating aircraftor other moving targets under conditions of poor visibility, as at nightor during fog, and the invention has. reference, more particularly, toimprovements in sound l0- cator receivers and associated apparatus ofthe type disclosed in my copending application now Patent 2,159,481,dated May 23, 1939.

inasmuch as sound location is always conducted in an ambient of audiblenoise, the sound oi' an aircraft or other object to be located can'- notbe rnade audible until its total sound level at the listening station orsome part of its sound spectrum reaches a level approximating that ofthe ambient. A reduction in ambient sound results in increased listeningrange, and hence sound-proong of sound locator receivers to reduceambient sound in the receiver is important. Ambient sound may be dividedinto two classes, i. e., general background and local noises, the

nrst consisting of sound that is generated at a distance from thereceiver and is air borne to the latter, and the second consisting ofsound generated within the receiver assembly and transmitted directly byvibration to the receiver sound track.' l

The principal object of the present invention is to provide novelimprovements in the sound insulation and vibration damping of sound1ocation receivers of the type disclosed in my,

above mentioned application, whereby ambient background sound reachingthe outside surfaces of the receiver are eiectively insulated againsttransmission to the receiver sound track, and ambient local sound isalso prevented from transmission to the sound track due to thoroughlocal vibration insulation of the receiver sound track.

Another object of the present invention lies in the provision of novelsound locator apparatus having listening helmets provided with earpieces especially designed to t around the users ears without applyingpressure directly thereto, and adapted to be readily centered withrespect to the ears, the same having adjustable sound track end piecesfor cooperating With-the'ear concha for preventing extraneous noisesandvibration from reaching'and distorting the sound traveling in the soundtrack and received through the sound receiver opening, the said helmetsbeing adapted to be readily and quickly attached to or detached from thesound receivers in use.

Still another object of thepresent invention is to provide a novel soundlccatorapparatu's having receivers so constructed and arranged that thesaine may be readily disassembled from their (Cl. lill-26) supportingpedestal for transport 'without dis-V connecting or breaking their soundtracks at any point, thereby enabling the readyreassenibly of thereceivers to their pedestal, when desired, Without in any 'Wayinterfering with the acoustical properties of the receivers.

A further object of the present invention lies in the provision o f anovel sound locator apparatus of the above character employing receiversor horns, each of which has the forward Ylo portion of its sound trackof conical shape, thereby obtaining the advantage of low rlctlonal lossadjacent the receiver opening, Whereas the rear portion of such soundtrack is oi exponential shape, thereby also obtaining the advantages of15 the delity of amplication or response over 'a wide frequency rangecharacteristic of the ex ponential horn.

Other objects and advantages will become apparent from the speciication,taken in connection 2@ With the accompanying drawings wherein theinvention is embodied in concrete form.

Fig. l is a view in elevation of the novel improved sound locatorapparatus of this invention;

Fig. 2 is a fragmentary sectional view of the 25 apparatus platformtaken approximately on line 2-2 of Fig. l. Y

Fig. 3 is a sectional view of an azimuth receiver supporting arm forhorn t of Fig. 1.

Fig. i is a central longitudinal sectional View of g@ a receiver.

1Fig; 5 is a fragmentary view illustrating the manner of detachablyconnecting a receiver arm l to the pedestal head.

Eig. 6 is a sectional view taken along S- of 35 Fig. 5.

Fig. '7 is a fragmentary sectional view of a `slightly modied form ofreceiver. l J l Fig. 3 is a sectional view of the connected supportingarms of an elevation receiver and theA 40 .common azimuth and elevationreceiver.

Fig. 9 is a View teken substantially along line d--Q oi Fig. 8. A Fig.lo is a perspective'view ci the horn supporting bracket.

Fig. l1 is a fragmentary sectional vview of a portion ofthe listeninghelmet in the region of the usersear. Y

Similar characters oi reference are used in all of the above gures toindicate corresponding 50 partsl Referring now to the said drawings, thesound locator apparatus comprises a suitable arrange.- rnent oflistening or sound collecting receivers or horns i, '2 and 3 mounted forboth turning in 55 azimuth and tilting in. elevation, the horn being acommon horn in that it cooperates withY horn i in making elevationdeterminations and with horn 3 in making azimuth determinations. Thehorns or receivers i, 2, 3 are carried by arms il, Ei, (i that aredetachably secured to a common cross shaft u@ which is, in turn, mountedfor turning in elevation on a head i by means oi' an elevation.handwheel Q connected through gearing lil for turning the horns i, El.Head i contains the sound lag correction and other apparatus forming nopart of the present invention, and is mounted for turning in azimuth ona pedestal t by means of an azimuth handwheel (not shown). Pedestal Siis mounted upon a circular platform i2 that is supported in a levelposition by adjustable leveling screws i3.

The horns or receivers E, 2, are smaller than the usual exponential hornand are carefully streamlined and soundproofed to avoid transmittingextraneous or ambient sounds through the receiver casing to the hornsound track, which extraneous sounds would render use of the apparatusmore dicult while decreasing the sensitivity and accuracy ci the same.Each receiver is constructed with a sound track hav- -ing the forwardportion thereof of conical shape defined by a 'conical shaped interiorwall tl preferably made of wood and havingr a rolled or bell mouth it,which merges into the outer conical casing or covering 2i, hereinafterdescribed, forming a smooth, streamlined exterior. This conical forwardvportion of the sound track possesses the advantage of low airfrictional loss, whereby it is possible to make the overall di mensionsofthe horn, including the horn mouth, much less than would be necessarywere a. pure exponential horn used for obtaining the same amplification.

The remainder of the soundtrack of the horn v is of exponential shape,thereby obtaining the fidelity of response over a wide frequency range,characteristic of the exponential horn. This exponential portion of thehorn comprises the goose neck portion i@ having its forward and upperend forming a continuation of conical portionv Hl and its reduced lowerend projecting into an exponential tube extending within the tube arm.and also constituting a portion of the sound track. The part of thegoose neck le adjoining Athe cone l) may be of hybrid shape tofacilitate the fia-ring or merging oi the exponential portion of thehorn into the conical portion thereof. The goose necls te is preferablymade of metal, the forward and upper end of which is provided with aflange il that is secured as by' screws to a split ring it xed upon therear portionof the conicelwall M. The rear ofthe goose neck portionlcurves downwardly and then this portion. extends forwardly intounderlying relation to the conical horn portion it and through anopening i@ in the tubular shank t@ oi a bracket 2 Il. At the bottom ofshank is a nxed collar which has an annular channel 22 embracing arrannular rubber ring 2t.

The bracket 2i (see Figs. i and lil) is shaped to conform to the conicalhorn portion EZB and has rstraps or bands 25, 25 attached thereto forerrtending around conical. portion it for securing and supporting thishorn portion'upon bracket Resilient bands 2G, 26', as of rubber, areinterposed between hornlportion le and straps. P5, iii in order toabsorb and prevent the sound. vibrations and shocks from beingtransmitted from bracket 2i to the interior oi the horn, or,

arcaica in other words, into the sound track or conduit.

The horn is provided with an outer substan tially conical casing orcover 21, preferably of sheet metal, that is attached at its forward endv to a split ring 29 fixed upon the outer edge portion of` the bell orrounded mouth l5, the rear portion of casing El being rounded at Ztl.The inner surface of the casing 2l' and the outer surface-of the hornproper are covered with suitable brous sound absorbing material fil suchas corrugated Seapack or other material, as glass wool.

Each of the sound receivers l, 2, 3 is attached to its respective arm 4,5, B as by set screws extending through apertures 3i' in a flange 3i onle one end of the arm, said screws being threaded into a collar 2li onthe shank 20 of horn bracket 2l. Arms Il, 5. and o have exponentialtubes and 34, respectively, therein that are continuations of the soundtracks othe horns, these tubes having their larger ends attached to theends of goose necks i6 and their smaller. ends attached to httings to,3S and 31. Tubes 32, and are preferably of rubber reenforced by exteriorspiral metal bands, and these tubes together with ttings 35, 36, 3'! arecovered with sound insulation material 3B. These lttings have nipples5i@ at their ends for engaging in the eX ponential tubes and in flexibletubes leading to the listening helmets. Thus, fitting is com' y nectedto the tube fill extending to the listening helmet i3 of the elevationoperator. Fitting hastwo outlets, one of which is connected to the tubelli, also leadingF to the listening helmet 135B of the elevationoperator, whereasthe other cut- '7 let is connected to a tube 42 leadingto the listen@ ing helmet fit of the azimuth operator. The fitting 3l(Fig. 6) is connected to tube M extending to the listening helmet d3 ofthe azimuth operator. ff

Tubes 40, M, 42 and 44 are preferably of rubber and are clamped upon thenipples 3Q of the various fittings by the novel arm base or casingconstruction illustrated in Fig. 8, in which it will be noted that thearms 4 and 5 are inter-4 connected and are attached at their junction byscrews 46 to an open-ended, cylindrical base member 45, the piane of theinner end of which is aligned with the center line of tube til so thatby tightening the attaching screws 48, the ends of the tube arms and thebase member titi are clamped upon the tube 40' by pressing this tubefirmly against the nipple 39. Similarly, tubes 4l and i2 are'securedbetween member i5 and an adjoining cylindrical base cover member lll,thereby securing these tubes to the respective nipples offitting 36.Similarly, tube to, connected to tting l'i in arm 6, kis bound upon thistting by a cylindrical arm base member screwed upon the end of the arm6. The inter connected arms t and 5 are removably attached to a angesupport 69 provided on the crs shaft llt, and the arm t is similarlyattached to a ange support liti' on this shaft by means of screwsextendingy through apertures in the cylindrical 05 members vand i8 andthreaded into apertures in the anges 49, lli; Y The iiexible rubberytubes leading to the heimets are adapted to be readily detached fromthe latter so that the operators may wear their 70 helmets when on dutyand need merely plug the tubes into their .helmets when desiring to usethe apparatus. Fig. l1 illustrates a typical construction ,oi thelistening helmets, wherein tube ti,

is shown provided with a nipple plug tft at its 'i5 arcaica end that isadapted te te plugged into a cyunend member 5t that is adapted to enterinto the ear concha. The conduit member '52 has a ring 5l which byengaging into a conforming annular groove in plug 5i, serves toyieldlngly retain this plug in the tube '52. The inner surface of thehelmet isshown provided with a ring-like boss or pad 58 of paddingmaterial adapted to extend around the listeners ear 55 so as to relievethe ear of pressure, While at the same time, engaging the head allaround the ear, serving to prevent extraneous noises from reaching theear. t

In using the helmet, the operator places the saine upon his head withthe tubes, such as tube di, disconnected and inserts his forengers intothe central apertures 52 of the helmet ear piece 'conduit member andshifts these tubes 52,- and' hence the ear pieces of the helmet, ifnecessary,- so as to align the tubes 52 with the ear conchas. Hethereupon turns the conduits or tubes 52 so as to thread these tubesinwardly or outwardly to bring the ear pieces 5t into comfortableposition within the ear conchas. When he desires to listen in at theapparatus, it is merely necessary to plug the nipple plugs 5l ofthetubes dii, di or 132, 'il, as the case may be, into the helmet earpiece sockets, and is assured of proper hearing inasmuch as these tubesare aligned directly with the centers of the listeners ears, theprojection of members 5t into the ear conchas serving to eliminate echoeects. The helmets, however, are not claimed per sein this applicationbut are claimed in my divisional or continuation applicav tion, Serialhlm-287,236, filed July 29, 1939, for

Listening helmets for sound locators.

Not only are the tube arms readily detachable from the head l, but thishead l is also readily detachable by means of screws 59 from thepedestal S, and this pedestal is also detachable by means of screws d@from the platform l2. This platform is made sound absorbent in order toprevent local noisesdue to walking thereon from being transmitted to thehorns, and consists essentially, as shown in Fig. 2, oi upper and lowermulti-ply boards @i and di that are attached to the upper and lowersurfaces *of4 an intermediate board t2, of balsa wood, which hasexcellent sound and Vibration absorbing qualities. Linoleum 't3 is showncoveringdhe upper surface oi the ply board di. A ring iid is attached tothe upper surface of platform i2, as by screws 65, to

. @i9 J dii. Leveling screws i3 are threaded into vertical which ringthe pedestal il is attached by screws `:mediate resilient ring et, as ofrubber, wherebyA the hornis oatecl within its outer casing, which,ineffect, is true `of the form of the invention shown in Fig. 4, whereinthe yieldable nature of the wood horn id provides ayieldable'support forthe horn.

inasmuch as the sound receivers are streamlined and haveall cornersrounded, they tend to greatly reduce local noise due to winds blowingpast them. Also, since the entire sound track is enclosed. either withinthe casing 2i or within arms d, 5 and t, winds cannot directly contactthe walls of the sound track to create noise for transmission intotheinterior thereof. Further, since the entire soundtrack is resilientlyenshrined and supported by rubber, there being no A direct metal tometal contact between any part of the 4sound track and the casing 2l orreceiver arms Il, 5 and 6, local vibration and noises such as those dueto gearing are absorbed and do not reach the sound track. Since theentire sound track as well as the casing 2i is sound-proofed with soundabsorbing'material, ambient sound.l

ampliiication and transmission to the ears of the listeners. In usingthe receivers of this invention, it is found that the ear is better ableto distinguish aircraft noise from the ambient noise due to the combinedconical and exponential structure of the sound tracks, such compoundstructure acting to amplify the range of aircraft noises t0 a greaterextent than the low frequency ambient sounds,

Asmany changes could be made in the above construction and man'yapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or Shown in the accompanying drawingsshall be interpreted as illustrative and not ,8K5

in a limiting sense.

What is claimed is:

i. l'n sound locator apparatus, a sound receiver having a compound soundconduit member consisting of a forward portion of conical shape-and arear portion of exponential shape, insulating means completely enclosingsaid sound conduit member with the exception oi' its forward open end,and a resilient mounting interposed between said conduit member and saidenclosing means, whereby sound vibrations of the apparatus are preventedfrom being transmitted to the conduit member.

2. In a sound locator apparatus, a plurality of sound receivers, hollowarms for supporting said sound receivers, said sound receivers havingcasings and sound conduit members extending withinthe receiver casingsand within their supporting arms, tubes connected to the ends of saidsound conduit members and extending outwardlyy through saidV arms forconnection to listeners helmets, and means for' supporting said arms forrotation together in' azimuthand elevation, and

means whereby said receivers and their arms may be disconnected fromsaid supporting means without severing said sound conduit members orsaid tubes.

3.A In a sound locator apparatus,'a supporting lpedestal, a soundabsorbingplatform for said pedestal comprising upper and lower layers ofply-boards and an intermediate layer of sound absorbent board.

e. In a sound locator apparatus, a sound absorbing platform comprisingupper and lower layers of ply-boards and' an' intermediate layer ofsound absorbent board, a pedestal disconv i.iectably mounted on saidplatform and having adisconnectable head, and sound receivers havingsupporting arms d isconnectably mounted on said head.

' ateneo@ 5. In an apparatus of the character described, asound receiverhaving a streamlined outer casing, a, supporting bracket within saidcasing', a horn mounted within said bracket within said casing soundabsorbent material between said mounting between said goose neck portionand said bracket to absorb shocks and sound vibra- Y tions.

6. In an apparatus of the character described, a sound receiver having astreamlined outer casing, a horn within said casing having a roundedmoutl'i portion and a goose neck rear portion, resilient supports forsaid horn within said casing so that at no point is there metal to metalconu tant between said horn and its casing, whereby said horn is free tovibrate within its casing, and insulating or sound absorbing material onthe exterior of said horn and the interior of said casing.

7. In sound locator apparatus, a sound receiver having a compound soundconduit consisting of a forward'conical wooden portion extendingrearwardly for the greater portion of the external dimension of the hornand a rear metallic portion of exponential interior shape communicatingwith the rear of said conical portion and reverseiy curved, andinsulating means completely enclos-a ing both portions of said. conduitexcept for the forward roundedl endthereof.

8. A sound locator comprising a pedestal, a .5

head rotatably mounted in azimuth thereon, a horizontal cross' shaftjournalled therein for ro tation in elevation, hollow arms detachablysecured to each end of said shaft, a single horn on one arm lying aboveor below the horizontal 10 ais of said shaft, a pair of horns spaced inelen Vation from. each other and secured to said other arm, one of saidpair Ilying in the same horizontal plane as said rst horn, the soundconduits leadm ing from each horn terminating in said arms ad- .l5

jacent their juncture with said cross shaft, and

sound listening helmets connected with"\the termini of the conduits,whereby the two listening structures mayl'be removed from the pedestalwithout breaking the sound paths. A

9. In an apparatus oi the character described, a sound receiver having astreamlined outer casing, a supporting bracket within said casing, ahorn having a rounded mouth merging into the forward portion of saidcasing, said horn beingga supported by said bracket within said casing,and sound absorbent material between said bracket and said horn forpreventing vibrations from the bracket from being transmitted to saidhorn.

FRANK R. HOUSE.

